As Costs Plummet, LED Use Soars

Wayne
Yamaguchi never planned to start his own light emitting diode (LED)-based
business. A former Hewlett-Packard engineer, Yamaguchi says LEDs were always
more of a diversion than a long-range goal. But that was before he began
pestering sales reps to discuss new LED technologies, before he began packing
his desk drawers full of LED samples, and before he began staying up all night
writing LED drivers for flashlights.

"It
was just a hobby," explains Yamaguchi, who now heads Yamaguchi Consulting,
which specializes in the creation of software drivers for LED-based products.
"I never made a decision to launch a business; it just turned out that way."

Yamaguchi
isn't the only engineer who's been swept up in the prevailing LED-based winds.
In Design News' recent reader survey of
LED technology, approximately 92 percent of respondents said they have used, or
plan to use, LEDs in their products. Moreover, their list of applications goes
far beyond the traditional lighting industry. Respondents said they've used
LEDs in automotive, aerospace, agriculture, defense, gaming, industrial and
medical applications, among many others. They've used them in the design of
bicycles, cameras and televisions. They've installed LED strips in pontoon boats for foot-level
lighting. They've placed them in robots and traffic lights. They've even put them in
refrigerators and food service equipment.

"The
ramp-up of LED commercialization is just starting," Yamaguchi says. "They're
like calculators were a long time ago. ?When calculators first came out, they were $200 and had four
functions. Now you can buy calculators that are far better for 99 cents. It's
going to be the same with LEDs."

Low Power Draw Is Key

Design News' survey provides some
insight as to why engineers are moving so fast into the LED arena. And while
respondents were strong in their support of this emerging technology, they were
varied in their reasons.

"There's
a combination of factors that are coming together to make LEDs appealing," says
Michael Bandel, an electrical engineer with Heatron Corp. who responded to the
survey. "The government is
pushing it, the technology is getting better and cheaper, and energy efficiency
is becoming more important."

Clearly,
declining costs play a big role in their decisions. The technology - which
calls on semiconductor chips to release energy as photons of light - has been
in existence for nearly 50 years but has only recently reached a price point
that makes it viable for widespread use.

Design News' LED survey bears out
the importance of the rapidly declining costs. One-third of those polled said
that they are now using LEDs because "the cost came down."

Moreover,
costs are expected to continue to decline, and many respondents who haven't yet
used the technology said they're preparing to jump on board when the price
drops to the right level. If prices follow an oft-quoted economic rule called
Haitz's Law (which predicts that LED cost per lumen falls by a factor of 10
every decade, while light generated per package rises by a factor of 20), many
expect to reach that decision point in the coming decade.

"The
big appeal is the performance versus the price," Bandel says. "Ten years ago,
the prices were very high and the performance was very low. But with each tick
of the clock, they're getting better."

Still,
Design News readers said the
price/performance curve pales in comparison to the importance of such
parameters as longer life and lower power draw. Several who spoke to Design News cited LED life expectancies of as much as
60,000 hours, which translates to almost seven consecutive years of use. Others
cited the high
lumen/Watt ratios as a primary reason for consideration.

The Design News survey showed those advantages were critically
important to the new breed of LED users. Asked, "What drew you to the
technology," 79.6 percent cited longer life. At the same time, 77.7 percent said they wanted
the lower power draw and 50 percent said they were attracted to the
technology's environmental advantages (respondents were encouraged to cite more
than one reason).

"I
need the most efficient, state-of-the-art lighting system on the planet," says
survey respondent Wayne Leonardi, founder of WTLS Services. "And that appears to be LEDs."

Heat, Drivers Top List of Concerns

Survey
respondents, however, universally indicated that it wasn't always easy to
integrate LEDs into their products. Many cited concerns with heat and software
drivers. Others said that costs haven't dropped enough yet. A few said they
worried about design complexity and about their own lack of understanding of
this emerging technology.

Still, about 43 percent of respondents said they consider
the choice of their LED driver to be "very important" and 32 percent described
LED drivers as "important." Only 16 percent considered drivers to be
unimportant, while about 9 percent said they simply don't understand LED
drivers.

Yamaguchi,
who specializes in creating drivers for LED flashlights, says that drivers have
a variety of important roles, not the least of which is the prevention of heat.
"A lot of LED flashlights have multi-levels and people don't always keep them
on the high setting," Yamaguchi explains.
"That way, they don't always get
hot."

Still,
heat came off as a big concern for the survey's respondents. Approximately 57
percent of them considered it an issue.

"Heat
is always a major factor," Yamaguchi
says. "LEDs radiate all their heat into a heat sink, whereas incandescents
radiate it out as infrared."

Among
those who considered heat to be an important issue, most plan to opt for a heat
sink to help deal with it. Forty-six percent said they will employ a heat sink,
while 38 percent said they will deal with heat by selecting the right driver.
Others said they've used, or plan to use, fans and synthetic air jets as a way
to dissipate heat.

"People
have rightly concluded that if LEDs are designed properly and heat-sinked
properly, they can last 50,000 hours or longer," Bandel points out.

Applications Abound

One area where readers were split was dimming
capability. About 46 percent of the respondents said dimming capability was
unimportant. Among the remainder, 30 percent said it was important, while 24
percent cited it as very important.

Respondents who want dimming tended to be more in the
lighting or construction businesses. Engineers pointed out that dimming is
particularly important in construction of new buildings and offices, where
builders typically keep an eye on future trends.

While lighting
(39%) was the most common application for future LEDs, however, uses for the
technology varied broadly, with no single application standing out. Industrial
controls and automation equipment (32%), consumer electronics (28%), and
automotive (21%) were among the most common applications for LEDs. Readers also
cited aerospace (12%), medical (12%), signage (12%), and defense (11%).

In general, however, Design News readers showed they are
bullish on the future of LEDs, even if they don't use them today. "Their
application and usage will take off ?for
sure, just based on energy efficiency alone," Bandel says.

Yamaguchi, who started out making drivers for LED
flashlights, adds that he has seen the trend spread to bicycle lights, helmet
lights, aquarium lights and a multitude of other applications. "LEDs are still
in their infancy," he concludes. "They're more expensive right now, but in 10
years they're going to be more cost competitive."

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